Al casting alloy

ABSTRACT

An Al casting alloy contains at least five of the following alloy components: Si: 2.5 to 7.5 wt.-%, Mg: 0.3 to 0.8 wt.-%, Cr: 0.10 to 0.35 wt.-%, Fe: 0.05 to 0.25 wt.-%, Mn: 0.1 to 0.8 wt.-%, Cu: 0.05 to 0.3 wt.-%, Sr: 0.01 to 0.06 wt.-%, Zr: &lt;0.006 wt.-%, Zn: 0.05 to 0.3 wt.-%, Admixtures (in total): &lt;0.2 wt.-%, supplemented to 100 wt.-% with Al, in each instance.

The invention relates to an aluminum casting alloy.

Various casting alloys are known from DE 10 2008 055 928 A1, DE 10 2012 108 590 A, DE 10 2013 108 127 A1, DE 10 2014 101 317 A1, DE 10 2015 111 020 A1.

Proceeding from this prior art, the invention is based on the task of making available an improved Al casting alloy, in particular a high-strength die-casting alloy, which demonstrates improved castability.

This is achieved by means of an Al casting alloy having the characteristics of claim 1. Further developments and advantageous embodiments of the invention are evident from the dependent claims.

The Al casting alloy according to the invention contains at least five of the following alloy components:

Si: 2.5 to 7.5 wt.-%, Mg: 0.3 to 0.8 wt.-%, Fe: 0.05 to 0.25 wt.-%, Mn: 0.1 to 0.8 wt.-%, Cu: 0.05 to 0.3 wt.-%, Sr: 0.010 to 0.060 wt.-%, Zr: <0.006 wt.-%, Zn: 0.05 to 0.3 wt.-%,

Admixtures (in total): <0.2 wt.-%, supplemented to 100 wt.-% with Al, in each instance.

The selection of alloy components according to the invention, on the order stated above, leads to a significant improvement in castability and in the mechanical properties, which is already found in the casting state, but, in particular, in the case of a cast component, after two hours of heat treatment, namely solution annealing and subsequent aging, wherein quenching of the cast component in water is preferably provided between these two heat treatment stages. For chassis applications, preferably for wheel-controlling components, very preferably for damping supports, wheel mounts and, in particular, pivot bearings, but also for control arms or transverse subframes, in particular integral subframes, higher mechanical characteristic values are obtained in this manner.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous for an area of use if Si is contained at a content of at least or of more than 2.5 wt.-%, preferably of at least or of more than 2.6 wt.-%, particularly preferably of at least or of more than 2.7 wt.-%, very particularly preferably of at least or of more than 2.8 wt.-%, even more preferably of at least or of more than 2.9 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous for the area of use if Si is contained at a content of maximally or of less than 3.5 wt.-%, preferably of maximally or of less than 3.4 wt.-%, particularly preferably of maximally or of less than 3.3 wt.-%, very particularly preferably of maximally or of less than 3.2 wt.-%, even more preferably of maximally or of less than 3.1 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous for an area of application if Si is contained at a content of at least or of more than 4.5 wt.-%, preferably of at least or of more than 4.6 wt.-%, particularly preferably of at least or of more than 4.7 wt.-%, very particularly preferably of at least or of more than 4.8 wt.-%, even more preferably of at least or of more than 4.9 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous for the area of application if Si is contained at a content of maximally or of less than 5.5 wt.-%, preferably of maximally or of less than 5.4 wt.-%, particularly preferably of maximally or of less than 5.3 wt.-%, very particularly preferably of maximally or of less than 5.2 wt.-%, even more preferably of maximally or of less than 5.1 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous for another area of application if Si is contained at a content of at least or of more than 6.5 wt.-%, preferably of at least or of more than 6.6 wt.-%, particularly preferably of at least or of more than 6.7 wt.-%, very particularly preferably of at least or of more than 6.8 wt.-%, even more preferably of at least or of more than 6.9 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous for the other area of application if Si is contained at a content of maximally or of less than 7.5 wt.-%, preferably of maximally or of less than 7.4 wt.-%, particularly preferably of maximally or of less than 7.3 wt.-%, very particularly preferably of maximally or of less than 7.2 wt.-%, even more preferably of maximally or of less than 7.1 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Mg is contained at a content of at least or of more than 0.3 wt.-%, preferably of at least or of more than 0.35 wt.-%, particularly preferably of at least or of more than 0.4 wt.-%, very particularly preferably of at least or of more than 0.45 wt.-%, even more preferably of at least or of more than 0.5 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Mg is contained at a content of maximally or of less than 0.8 wt.-%, preferably of maximally or of less than 0.75 wt.-%, particularly preferably of maximally or of less than 0.7 wt.-%, very particularly preferably of maximally or of less than 0.65 wt.-%, even more preferably of maximally or of less than 0.60 wt.-%, even more preferably of maximally or of less than 0.55 wt.-%, even more preferably of maximally or of less than 0.50 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Mn is contained at a content of at least or of more than 0.1 wt.-%, preferably of at least or of more than 0.2 wt.-%, particularly preferably of at least or of more than 0.3 wt.-%, very particularly preferably of at least or of more than 0.4 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Mn is contained at a content of maximally or of less than 0.8 wt.-%, preferably of maximally or of less than 0.75 wt.-%, particularly preferably of maximally or of less than 0.7 wt.-%, very particularly preferably of maximally or of less than 0.65 wt.-%, even more preferably of maximally or of less than 0.60 wt.-%, even more preferably of maximally or of less than 0.55 wt.-%, even more preferably of maximally or of less than 0.50 wt.-%, even more preferably of maximally or of less than 0.45 wt.-%, even more preferably of maximally or of less than 0.40 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Cr is contained at a content of at least or of more than 0.25 wt.-%, preferably of at least or of more than 0.26 wt.-%, particularly preferably of at least or of more than 0.27 wt.-%, very particularly preferably of at least or of more than 0.28 wt.-%, even more preferably of at least or of more than 0.29 wt.-%, even more preferably of at least or of more than 0.30 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Cr is contained at a content of maximally or of less than 0.35 wt.-%, preferably of maximally or of less than 0.34 wt.-%, particularly preferably of maximally or of less than 0.33 wt.-%, very particularly preferably of maximally or of less than 0.32 wt.-%, even more preferably of maximally or of less than 0.31 wt.-%, even more preferably of maximally or of less than 0.30 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Cr is contained at a content of at least or of more than 0.10 wt.-%, preferably of at least or of more than 0.11 wt.-%, particularly preferably of at least or of more than 0.12 wt.-%, very particularly preferably of at least or of more than 0.13 wt.-%, even more preferably of at least or of more than 0.14 wt.-%, even more preferably of at least or of more than 0.15 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Cr is contained at a content of maximally or of less than 0.20 wt.-%, preferably of maximally or of less than 0.19 wt.-%, particularly preferably of maximally or of less than 0.18 wt.-%, very particularly preferably of maximally or of less than 0.17 wt.-%, even more preferably of maximally or of less than 0.16 wt.-%, even more preferably of maximally or of less than 0.15 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Fe is contained at a content of at least or of more than 0.05 wt.-%, preferably of at least or of more than 0.07 wt.-%, particularly preferably of at least or of more than 0.09 wt.-%, very particularly preferably of at least or of more than 0.11 wt.-%, even more preferably of at least or of more than 0.13 wt.-%, even more preferably of at least or of more than 0.15 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Fe is contained at a content of maximally or of less than 0.25 wt.-%, preferably of maximally or of less than 0.23 wt.-%, particularly preferably of maximally or of less than 0.21 wt.-%, very particularly preferably of maximally or of less than 0.19 wt.-%, even more preferably of maximally or of less than 0.17 wt.-%, even more preferably of maximally or of less than 0.15 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Cu is contained at a content of at least or of more than 0.05 wt.-%, preferably of at least or of more than 0.10 wt.-%, particularly preferably of at least or of more than 0.15 wt.-%, very particularly preferably of at least or of more than 0.20 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Cu is contained at a content of maximally or of less than 0.30 wt.-%, preferably of maximally or of less than 0.25 wt.-%, particularly preferably of maximally or of less than 0.20 wt.-%, very particularly preferably of maximally or of less than 0.15 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Sr is contained at a content of at least or of more than 0.010 wt.-%, preferably of at least or of more than 0.015 wt.-%, particularly preferably of at least or of more than 0.020 wt.-%, very particularly preferably of at least or of more than 0.025 wt.-%, even more preferably of at least or of more than 0.030 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Sr is contained at a content of maximally or of less than 0.060 wt.-%, preferably of maximally or of less than 0.050 wt.-%, particularly preferably of maximally or of less than 0.045 wt.-%, very particularly preferably of maximally or of less than 0.040 wt.-%, even more preferably of maximally or of less than 0.035 wt.-%.

The Al casting alloy according to the invention can contain admixtures, for example contaminants related to production, such as Pb, Ni, etc. These can also be desired admixtures, which increase the strength of the Al casting alloy, or of components cast from it, without having a negative effect on the castability of the Al casting alloy.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if admixtures, in total, are contained at a content of maximally or of less than 0.2 wt.-%, preferably of maximally or of less than 0.18 wt.-%, particularly preferably of maximally or of less than 0.16 wt.-%, very particularly preferably of maximally or of less than 0.14 wt.-%, even more preferably of maximally or of less than 0.12 wt.-%, even more preferably of maximally or of less than 0.10 wt.-%, even more preferably of maximally or of less than 0.08 wt.-%, even more preferably of maximally or of less than 0.06 wt.-%, even more preferably of maximally or of less than 0.04 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if other admixtures, in total, are contained at a content of at least or of more than 0.01 wt.-%, preferably of at least or of more than 0.03 wt.-%, particularly preferably of at least or of more than 0.05 wt.-%, very particularly preferably of at least or of more than 0.07 wt.-%, even more preferably of at least or of more than 0.09 wt.-%, even more preferably of at least or of more than 0.11 wt.-%, even more preferably of at least or of more than 0.13 wt.-%, even more preferably of at least or of more than 0.15 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Zr is contained at a content of maximally or of less than 0.006 wt.-%, preferably of maximally or of less than 0.005 wt.-%, particularly preferably of maximally or of less than 0.004 wt.-%, very particularly preferably of maximally or of less than 0.003 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Zr is contained at a content of at least or of more than 0.001 wt.-%, preferably at a content of at least or of more than 0.002 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Zn is contained at a content of at least or of more than 0.05 wt.-%, preferably of at least or of more than 0.10 wt.-%, particularly preferably of at least or of more than 0.15 wt.-%, very particularly preferably of at least or of more than 0.20 wt.-%.

For optimization of castability and/or of the mechanical characteristic values, it can be advantageous if Zn is contained at a content of maximally or of less than 0.3 wt.-%, preferably of maximally or of less than 0.25 wt.-%, particularly preferably of maximally or of less than 0.20 wt.-%, very particularly preferably of maximally or of less than 0.15 wt.-%.

It can be advantageous if the Al casting alloy is a die-casting alloy.

It can be advantageous if the Al casting alloy is a vacuum die-casting alloy.

Accordingly, the invention also relates to a method for production of a cast component from an Al casting alloy according to the invention, in which the die-casting method, preferably the vacuum die-casting method, as it is described in DE 10 2010 046 041 A1, for example, is used.

It can be advantageous if the cast components cast from the Al casting alloy according to the invention are subjected to two-stage heat treatment, namely solution annealing and subsequent hot aging. It can be advantageous if the cast component is quenched in water between the two heat treatment stages.

It can be practical if the cast component, after the casting process, is solution-annealed between 480° C. and 520° C. for 1 h 30 min to 4 h, preferably between 480° C.-500° C. for 2 h 30 min to 3 h 30 min, particularly for 2 h 45 min to 3 h 15 min 8 to 9 h, very particularly preferably between 485° C. and 495° C., in particular for 2 h 45 min to 3 h 15 min.

It can be practical if the cast component, after the casting process, is tempered between 175° C. and 210° C. for 2 h 30 min to 5 h 30 min, in particular for 3 h to 5 h, preferably between 175° C. and 190° C. for 3 h to 5 h, in particular for 3 h 30 min to 4 h 30 min, particularly preferably between 175° C. and less than 185° C. for 3 h 30 min to 4 h 30 min, in particular for 3 h 45 min to 4 h 15 min.

The invention furthermore provides for the use of the Al casting alloy according to the invention or of a particularly heat-treated cast component made from the Al casting alloy according to the invention for chassis parts of motor vehicles, in particular for transverse or integral subframes or for wheel-guiding components of motor vehicles, very particularly preferably for damper stilts, wheel mounts or pivot bearings of motor vehicles.

The very good castability of the Al casting alloy according to the invention allows production of a cast piece that is free of holes or cavities.

Cast components according to the invention, which are produced from an Al casting alloy according to one of the claims and/or according to a method according to one of the claims are characterized, after heat treatment by a tensile yield strength R_(p)0.2 of >250 MPa, preferably of 260 to 280 MPa, and/or an elongation to rupture A5 of >6%, preferably of 7 to 9%, particularly preferably of 7.5 to 8.5%, and/or a tensile strength R_(m) of 280 to 300 MPa, preferably of >280 MPa.

EXAMPLE

To determine the mechanical properties of an alloy according to the invention, which contains 3.4 wt.-% Si, 0.5 wt.-% Mg, 0.27 wt.-% Cr, 0.09 wt.-% Fe, 0.40 wt.-% Mn, 0.05 wt.-% Ti, 0.009 wt.-% Cu, 0.22 wt.-% Sr, 0.002 wt.-% Zr, 0.003 wt.-% Zn, and contaminants of less than 0.1 wt.-%, supplemented to 100 wt.-% with Al, in each instance, test rods according to DIN 50125 are cut from a component produced by means of a vacuum die-casting method, in particular from a suspension strut dome, wherein the component previously received heat treatment (solution annealing 490° C. for 3 h, quenching in water, hot aging 480° C. for 4 h). Casting of comparison components, namely from an AlSi10MgMn alloy, an AlSi3MgCrMn alloy according to the invention, and an AlSi5MgCrMn alloy according to the invention, and their subsequent heat treatment take place under the same conditions. The alloys to be compared differ in terms of their silicon content and chromium content. The sample rod is removed at the same location of the component, in each instance, in the present case of the suspension strut dome. The mechanical properties of tensile strength R_(m), tensile yield strength R_(p)0.2, and elongation to rupture A5 are determined in accordance with DIN10002.

R_(m) [MPa] R_(p)0.2 [MPa] A5 [%] AlSi10MgMn (standard 435 alloy) 284 237 6-8 AlSi3MgCrMn alloy according to the 285 254 6-8 invention AlSi5MgCrMn alloy according to the 301 242 7-9 invention 

1. An Al casting alloy that contains at least five of the following alloy components Si: 2.5 to 7.5 wt.-%, Mg: 0.3 to 0.8 wt.-%, Cr: 0.10 to 0.35 wt.-%, Fe: 0.05 to 0.25 wt.-%, Mn: 0.1 to 0.8 wt.-%, Cu: 0.05 to 0.3 wt.-%, Sr: 0.01 to 0.06 wt.-%, Zr: <0.006 wt.-%, Zn: 0.05 to 0.3 wt.-%, Admixtures (in total): <0.2 wt.-%, supplemented to 100 wt.-% with Al, in each instance.
 2. The Al casting alloy according to claim 1, wherein Si is contained at a content of at least or more than 2.5 wt.-%, preferably of at least or of more than 2.6 wt.-%, particularly preferably of at least or of more than 2.7 wt.-%, very particularly preferably of at least or of more than 2.8 wt.-%, even more preferably of at least or of more than 2.9 wt.-%.
 3. The Al casting alloy according to claim 1, wherein Si is contained at a content of maximally or of less than 3.5 wt.-%, preferably of maximally or of less than 3.4 wt.-%, particularly preferably of maximally or of less than 3.3 wt.-%, very particularly preferably of maximally or of less than 3.2 wt.-%, even more preferably of maximally or of less than 3.1 wt.-%.
 4. The Al casting alloy according to claim 1, wherein Si is contained at a content of at least or of more than 4.5 wt.-%, preferably of at least or of more than 4.6 wt.-%, particularly preferably of at least or of more than 4.7 wt.-%, very particularly preferably of at least or of more than 4.8 wt.-%, even more preferably of at least or of more than 4.9 wt.-%.
 5. The Al casting alloy according to claim 1, wherein Si is contained at a content of maximally or of less than 5.5 wt.-%, preferably of maximally or of less than 5.4 wt.-%, particularly preferably of maximally or of less than 5.3 wt.-%, very particularly preferably of maximally or of less than 5.2 wt.-%, even more preferably of maximally or of less than 5.1 wt.-%.
 6. The Al casting alloy according to claim 1, wherein Si is contained at a content of at least or of more than 6.5 wt.-%, preferably of at least or of more than 6.6 wt.-%, particularly preferably of at least or of more than 6.7 wt.-%, very particularly preferably of at least or of more than 6.8 wt.-%, even more preferably of at least or of more than 6.9 wt.-%.
 7. The Al casting alloy according to claim 1, wherein Si is contained at a content of maximally or of less than 7.5 wt.-%, preferably of maximally or of less than 7.4 wt.-%, particularly preferably of maximally or of less than 7.3 wt.-%, very particularly preferably of maximally or of less than 7.2 wt.-%, even more preferably of maximally or of less than 7.1 wt.-%.
 8. The Al casting alloy according to claim 1, wherein Mg is contained at a content of at least or of more than 0.3 wt.-%, preferably of at least or of more than 0.35 wt.-%, particularly preferably of at least or of more than 0.4 wt.-%, very particularly preferably of at least or of more than 0.45 wt.-%, even more preferably of at least or of more than 0.5 wt.-%.
 9. The Al casting alloy according to claim 1, wherein Mg is contained at a content of maximally or of less than 0.8 wt.-%, preferably of maximally or of less than 0.75 wt.-%, particularly preferably of maximally or of less than 0.7 wt.-%, very particularly preferably of maximally or of less than 0.65 wt.-%, even more preferably of maximally or of less than 0.60 wt.-%, even more preferably of maximally or of less than 0.55 wt.-%, even more preferably of maximally or of less than 0.50 wt.-%.
 10. The Al casting alloy according to claim 1, wherein Mn is contained at a content of at least or of more than 0.1 wt.-%, preferably of at least or of more than 0.2 wt.-%, particularly preferably of at least or of more than 0.3 wt.-%, very particularly preferably of at least or of more than 0.4 wt.-%.
 11. The Al casting alloy according to claim 1, wherein Mn is contained at a content of maximally or of less than 0.8 wt.-%, preferably of maximally or of less than 0.75 wt.-%, particularly preferably of maximally or of less than 0.7 wt.-%, very particularly preferably of maximally or of less than 0.65 wt.-%, even more preferably of maximally or of less than 0.60 wt.-%, even more preferably of maximally or of less than 0.55 wt.-%, even more preferably of maximally or of less than 0.50 wt.-%, even more preferably of maximally or of less than 0.45 wt.-%, even more preferably of maximally or of less than 0.40 wt.-%.
 12. The Al casting alloy according to claim 1, wherein Cr is contained at a content of at least or of more than 0.25 wt.-%, preferably of at least or of more than 0.26 wt.-%, particularly preferably of at least or of more than 0.27 wt.-%, very particularly preferably of at least or of more than 0.28 wt.-%, even more preferably of at least or of more than 0.29 wt.-%, even more preferably of at least or of more than 0.30 wt.-%.
 13. The Al casting alloy according to claim 12, wherein Cr is contained at a content of maximally or of less than 0.35 wt.-%, preferably of maximally or of less than 0.34 wt.-%, particularly preferably of maximally or of less than 0.33 wt.-%, very particularly preferably of maximally or of less than 0.32 wt.-%, even more preferably of maximally or of less than 0.31 wt.-%, even more preferably of maximally or of less than 0.30 wt.-%.
 14. The Al casting alloy according to claim 1, wherein Cr is contained at a content of at least or of more than 0.10 wt.-%, preferably of at least or of more than 0.11 wt.-%, particularly preferably of at least or of more than 0.12 wt.-%, very particularly preferably of at least or of more than 0.13 wt.-%, even more preferably of at least or of more than 0.14 wt.-%, even more preferably of at least or of more than 0.15 wt.-%.
 15. The Al casting alloy according to claim 14, wherein Cr is contained at a content of maximally or of less than 0.20 wt.-%, preferably of maximally or of less than 0.19 wt.-%, particularly preferably of maximally or of less than 0.18 wt.-%, very particularly preferably of maximally or of less than 0.17 wt.-%, even more preferably of maximally or of less than 0.16 wt.-%, even more preferably of maximally or of less than 0.15 wt.-%.
 16. The Al casting alloy according to claim 1, wherein Fe is contained at a content of at least or of more than 0.05 wt.-%, preferably of at least or of more than 0.07 wt.-%, particularly preferably of at least or of more than 0.09 wt.-%, very particularly preferably of at least or of more than 0.11 wt.-%, even more preferably of at least or of more than 0.13 wt.-%, even more preferably of at least or of more than 0.15 wt.-%.
 17. The Al casting alloy according to claim 1, wherein Fe is contained at a content of maximally or of less than 0.25 wt.-%, preferably of maximally or of less than 0.23 wt.-%, particularly preferably of maximally or of less than 0.21 wt.-%, very particularly preferably of maximally or of less than 0.19 wt.-%, even more preferably of maximally or of less than 0.17 wt.-%, even more preferably of maximally or of less than 0.15 wt.-%.
 18. The Al casting alloy according to claim 1, wherein Cu is contained at a content of at least or of more than 0.05 wt.-%, preferably of at least or of more than 0.10 wt.-%, particularly preferably of at least or of more than 0.15 wt.-%, very particularly preferably of at least or of more than 0.20 wt.-%.
 19. The Al casting alloy according to claim 1, wherein Cu is contained at a content of maximally or of less than 0.30 wt.-%, preferably of maximally or of less than 0.25 wt.-%, particularly preferably of maximally or of less than 0.20 wt.-%, very particularly preferably of maximally or of less than 0.15 wt.-%.
 20. The Al casting alloy according to claim 1, wherein Sr is contained at a content of at least or of more than 0.010 wt.-%, preferably of at least or of more than 0.020 wt.-%, particularly preferably of at least or of more than 0.030 wt.-%, very particularly preferably of at least or of more than 0.035 wt.-%, even more preferably of at least or of more than 0.040 wt.-%. 21-29. (canceled) 